/**

Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016.  All rights reserved.

Contact:
     SYSTAP, LLC DBA Blazegraph
     2501 Calvert ST NW #106
     Washington, DC 20008
     licenses@blazegraph.com

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/
/*
 * Created on Aug 26, 2010
 */

package com.bigdata.util.concurrent;

import java.util.concurrent.CancellationException;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

import junit.framework.TestCase2;

import com.bigdata.util.InnerCause;

/**
 * Test suite for {@link Haltable}.
 * 
 * @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
 * @version $Id$
 */
public class TestHaltable extends TestCase2 {

    /**
     * 
     */
    public TestHaltable() {
    }

    /**
     * @param name
     */
    public TestHaltable(String name) {
        super(name);
    }

    /**
     * Unit test where the {@link Haltable} is cancelled.
     * 
     * @throws ExecutionException 
     */
    public void test_cancel() throws InterruptedException, ExecutionException {

        final Haltable<Void> f = new Haltable<Void>();
        
        assertFalse(f.isDone());
        assertFalse(f.isCancelled());
        assertNull(f.getCause());

        assertTrue(f.cancel(true/* mayInterruptIfRunning */));
        
        assertTrue(f.isDone());
        assertTrue(f.isCancelled());
        assertNull(f.getCause());

        try {
            f.get();
            fail("Expecting: " + CancellationException.class);
        } catch (CancellationException ex) {
            if (log.isInfoEnabled())
                log.info("Ignoring expected exception: " + ex);
        }

        assertTrue(InnerCause.isInnerCause(f.getAsThrownCause(),
                InterruptedException.class));

    }

    /**
     * Unit test where the {@link Haltable} returns the result of its
     * computation.
     * 
     * @throws ExecutionException
     * @throws InterruptedException
     */
    public void test_get() throws InterruptedException, ExecutionException {

        final Haltable<Long> f = new Haltable<Long>();

        assertFalse(f.isDone());
        assertFalse(f.isCancelled());
        assertNull(f.getCause());

        final Long result = Long.valueOf(12);

        // set the result.
        f.halt(result);

        assertTrue(result == f.get());

        assertTrue(f.isDone());
        assertFalse(f.isCancelled());
        assertNull(f.getCause());
        assertNull(f.getAsThrownCause());

        assertFalse(f.cancel(true/*mayInterruptIfRunning*/));

        assertTrue(result == f.get());

    }

    public void test_get_timeout() throws InterruptedException, ExecutionException {

        final Haltable<Long> f = new Haltable<Long>();

        assertFalse(f.isDone());
        assertFalse(f.isCancelled());
        assertNull(f.getCause());

        final Long result = Long.valueOf(12);

        {
            final long timeout = TimeUnit.SECONDS.toNanos(1L);
            final long begin = System.nanoTime();
            try {
                f.get(timeout, TimeUnit.NANOSECONDS);
                fail("Expecting: " + TimeoutException.class);
            } catch (TimeoutException e) {
                // ignore
            }
            final long elapsed = System.nanoTime() - begin;
            if (elapsed < timeout || (elapsed > (2 * timeout))) {
                fail("elapsed=" + elapsed + ", timeout=" + timeout);
            }
        }

        // set the result.
        f.halt(result);

        assertTrue(result == f.get());

        assertTrue(f.isDone());
        assertFalse(f.isCancelled());
        assertNull(f.getCause());
        assertNull(f.getAsThrownCause());

        assertFalse(f.cancel(true/*mayInterruptIfRunning*/));

        assertTrue(result == f.get());

    }
    
}
